1. Field of the Invention
The present invention relates to projection devices such as liquid crystal projectors, projection image display devices and optical engines such as reflective image display projectors and beam type rear projection television for projecting images on a screen using light pipe devices such as liquid crystal panels or image display elements, and relates in particular to technology for beaming a plurality of light colors onto different light pipe element locations using a rotating multisurface element, and changing the beaming locations in sequence.
2. Description of the Related Art
An optical unit is known in the related art for passing light from a light source through a first and a second array lens, a polarized beam splitter (PBS) and a collimator lens, and then separating the light into red light, blue light and green light by using a plurality of dichroic mirrors, and then changing the optical paths of each separated (colored) light by means of respective rotating prisms and beaming each light onto respectively different locations on a light pipe element (hereafter simply referred to as a display element or image display element) and also scroll each light beam in sequence in a fixed direction on the display element locations.